Photographic elements with lightfiltering layers



Aug. 12, 1952 w. R. SANER 2,606,834

PHOTOGRAPHIC ELEMENTS WITH LIGHT-FILTERING LAYERS,

Filed July 19. 1949 FIG].

GELATIN SILVER HALIDE ELATIN SUBSTRATUM CELLULOSE ACETATE BASE ANTI'HALATION LAYER COMPRISING AN {ACID DYE SALT OF POLY-Z-VINYLPYRIDINE BENZAMIDO] BENZALDEHYDE POLYVINYL ACETAL BLUE- SENSITIVE SILVER HALIDE LAYER POLY 2 -VIN YLPYRIDINE- TARTRAZINE SALT FILTER LAYER m-(3- METHYL SALICYLAMIDOI BENZALDEHYDE POLYVINYL ACETAL GREEN-SENSITIVE SILVER HALIDE LAYER CELLULOSE NITRATE BASE ANTIHALATION LAYER COMPRISING POLYVINYL ALCOHOL AND INK BLUE 9 {m-[p-5IETHYL CARBONATO-3-METHYL-l- PYRAZOLYLI ANTIHALATION LAYER COMPRISING POLYVINYL ALCOHOL AND INK BLUE INVEYTOR. WILL/AM RUSSELL SANER BY A TTORNE Y.

Patented Aug. 12, 1952 PHOTOGRAPHIC ELEMENTS WITH LIGHT- FILTERING LAYERS.

William Russell Saner, Plainfield, N. J assigncr to E. I. du Pontde Nemours and Company, Wilmington;.Del.,. a; corporation of Delaware ApplicationIJuly-19, 1949, Serial N0. 105,665

- I l? 'Ihisfinventi on relatesto photography and more particularly to photographic. elements such as film. papers, and printing plates which contain a lightefi'ltering' layer composedofa salt of apolyvinylpyridine with an acid dye. Still'moreparticularly it relates to photographic film elements which contain a layer composed'of a salt of 1a polyvinylpyridine'withv a dye containinga carboxylic or sulfonic acid. group;

An object of this invention" isito'provide -improvements'in the art of photography; Another objectis to provide new and useful photographic films, papers, and plates. Another object is to provide photographic film elements with a novel lightrfiltering layer composed ofa salt of a polyvinylpyridine'with" a;dyecontaining a sulfonic or. carboxylic acid group or a mixtureof such salts; A- still further-object is to provide photo'- graphicfilm elements with an anti-halation layer composed-of a saltof polyvinylpyridine with adye ontaininga suli onicor-carboxylic acid group. Still other objects will be apparent'from the following-description of the invention; r

g It. has been discovered that" water-insoluble vinylp'yridine polymers which are soluble in 1% acetic acid form" polymeric salts withacid dyes" of high molecular weight which contain su-lfonic acidor'carboxylicacid groups and the resulting salts, formpractical light-absorbing" layers in photographic films and plates. These polymeric salts iorn'rhard, smooth layers which are resinlike lid-appearance but are colored in accordance with'the" tinctorial properties of the dyes gused to fo'rm thesalts; V w The. salts of v-imylpyridine polymers with the acid dyes may be prepared byadmixing m an aqueous medium a vinylpyridinepolymer with an acid dye "containing a sulfonic acid- -or carboxylic acid group or groups or-- a -mi-xture of acid; dyes. The polymeric polyvinylpyridine salts precipitate out and canbe purified by washing in "water and reerystall-izing from an organic" solvent, e; g., methanol, ethanol; etc. The acid dyes used-to form the salts confera color upon-the resulting polymeric salt substantially the same as that of the originaldye. The polymericfdyesalt .or-mixe .ture of such salts can be. dissolved in asolvent such'as' methanol or ethanol or a mixture ofsuch solvents, and then coated onto asupport .or onto a light-sensitive silver halide layer. on .aIsupport 99 Claims.

. 0 to form a light-filtering layer. alight-sensitive 5 2 silver-halide layer may then be coated on the polymeric dye salt layer. Removable anti-halation layers can be made by depositing the polyvinylpyridine salt with the acid dye on one side of a transparent base, e.'g., a-film or transparentized paper; and a colloid'silverhalideemulsion layer, or a-plurality of such layerswhich are differentially sensitized may bee-deposited on the other side of the base. The layer may be' readily removed in' a dilute acid bath which may be 1 an acid stop-bathor an acid fixingbath after development.

Novel light-filtering layers may' be made by depositing" the polymeric salt of a polyvinylpyridine'with-an acid dye onto a colloid'silver halide emulsion layer which is disposed on a suit able-film base-or on another'colloid' silver halide emulsion'l-ayer-w-hichis disposed on such a base. A photographic silver halide emulsion layer is then coated onto the novel light-filterihg- 'layer; Therespective silver halide emulsions are gener-' ally *difierentially sensitized so'that they record light'from -difierent primary color regions of the spectrum: Thus; a yellow' dye salt can be used in' alight-filtering layer where it is desired to absorb or prevent blue light from exposing alo'wer gelatino silver halide emulsion layer which is also sensitive to green o-rred light. In the case of a multi-layerfilm containing three differen tiallysensitized-silver halide emulsion layers; a layer'composed-of a yellow dye salt of raj-polyvinylpyridine is placed between the-outer blue sensitive laye-r-and-the nextgreen blind red sensitive silver halide emulsion layer; A layer composed of rea dye salt ofa polyvinylpyridine is placed betweenthe latter layer" and the bottom layer-which is a-green sensitive silver halide emulsion layer. 7 These layers of course are'castfrom solution in making the multilayer'film element. Any dye salt which possesses the property 'of absorbing: actinic light which will exposethe silver halide emulsion layers of the elements can be used for making the anti-halation. layersf The dye must be: absorptive. of "light of wavelengths" to which:.the..emulsion issensitized. In some cases, mixtures of .twozor more different. dye: salts o-f the pol-Winylpyridinese-maywbe usedziini'order. tov acquire-; adequate lighte-absorption: In the 1 case of daylight-loading ibackin s :the: layers are usually black and absorb all wavelengths of visible light.

. Polyvinylpyridines: or I vinyl-pyridineipol-ymers can be made by polymerizing a monomeric vinylpyridine of relatively low molecular weight, e. g., alpha-, betaor gamma-vinylpyridine. or a homologue thereof containing an alkyl radical of 1 to 4 carbon atoms in the pyridine ring, in a liquid medium bythe aid of a vinyl compound polymerization catalyst. An organic solvent solution can be used as the liquid medium, if desired. However, the organic solvent should be inert so that it will not interfere with the polymerization reaction. The polymers can be made by emulsion polymerization, if desired, and bulk polymerization methods are effective. The polymerization is preferably carried out in an aqueous acid solution or medium in the presence of a peroxy compound catalyst at temperatures from about 20 to 50 C. for a period of or less to 200 or more hours. The proportion of mineral acid, e. g hydrochloric or sulfonic acid, used may vary over a fairly wide range, e. g., from 0.5 to 2.5 moles of acid per mole of vinylpyridine monomer. V

The resulting solution may be diluted with water and admixed with a basic solution, e. g., aqueous sodium hydroxide, whereupon a vinylpyridine polymer precipitates and can be washed and dried. In some cases, it is desirable to incorporate a neutralizing agent in the washing solutions to remove any remaining acid catalyst.

The vinylpyridine polymers described above, including the lower alkyl substituted polyvinylpyridines, are of relatively high molecular weight and generally are mixtures of polymeric molecules of various chain lengths. The polymers are soluble in 1% aqueous acetic acid and in similar Suitable compounds for copolymerization are styrene, acrylic esters and amides, alpha-alkyl substituted acrylic esters and amides, and acrylonitrile and methacrylonitrile. Among the specific useful compounds of this type are methyl and ethyl acrylates; methacrylamide and N- methylacrylamidey acrylonitrile and methacrylonitrile. Mixtures of two or more of the latter compounds can beused, if desired. Y

The proportion of the acid dye which is used to make the polymeric acid dye salt of the polyvinylpyridine may vary over fairly wide limits, e. g., from 0.01 to 0.5 mol of dye per mol of vinylpyridine monomer or vinylpyridine. In

general, however, amounts of dye salt from 0.05

to 0.10'mol per mol of vinylpyridine will besufficient and constitutes a preferred range.-

In the case of dyes which have their carboxylic or sulfonic acid group or groups neutralized by a water-soluble salt-forming cation, e. g., alkali metal, ammonium, or amine, the salt-forming reaction with the vinylpyridine polymers must be carried out under acid conditions so that these salts are converted into the free acids. Various organic and inorganic acids may be used. Suitable acids include hydrochloric, sulfuric, and acetic. The acid concentration should be rather eat n;

4 low, and sumcient to give a pH in the range of 2 to 3.

It is not necessary to coat the anti-halation layer composed of the polyvinylpyridine acid dye salt directly on the transparent or light-transmitting support. On the contrary, a water-soluble or dilute acid soluble colloid material may be first deposited on the base and the vinylpyridine dye salt deposited thereon. Among the water-soluble colloid materials which can be used are polyvinyl alcohol, hydrolyzed ethylene, vinyl acetate copolymers, gelatin, cellulose ethers, e. g., water-soluble methyl cellulose, cellulose acetate phthalate alkali metal salts. As dilute acid soluble colloids there may be mentioned the polyvinyl pyridines described in U. S. Patent 2,448,525 and deacetylated chitin.

In the preferred aspect of the invention, the polymers of the unsubstituted alphaor 2-viny1- pyridine are used to react with the acid dyes. Poly-2-pyridine is a water-insoluble synthetic resin which is soluble in alcohols, e. g., methyl, ethyl, propyl, and butyl alcohols, and mixtures of such alcohols and also mixtures of these alcohols with ketones, e. g., acetone, methyl ethyl ketone, methyl propyl ketone, and methyl isobutyl ketone. They are also soluble in certain chlorinated hydrocarbons, e. g., trichlorethane and methylene chloride. The polymers form clear, light-colored, non-tacky films or coatings which are readily and completely soluble in dilute aqueous acids, e. g., 1% acetic acid, hydrochloric, sulfamic, sulfuric, phosphoric, and oxalic acids.

The invention will be further illustrated but is not intended to be limited by the following examples:

Example ,I

0.4 gram of Pontacyl Fast Black BBO (Colour Index 307) in aqueous solution was added to 20 milliliters of a 10% solution of poly-2-vinylpyridine (which was soluble in aqueous acetic acid and formed a clear hard resin-like film), in methanol, whereby a polymeric salt of the acid dye with the poly-2-vinylpyridine was precipitated. The polymeric salt or complex which was isolated was soluble in methanol and ethanol and showed no tendency to bleed in water. A 10% solution of the acid dye salt of poly-2-vinylpyridine in methanol was applied to one surface of a clear cellulose acetate film base I as shown in Fig. 1 of the accompanying drawing which constitutes a part of this specification and dried forming a continuous, hard, clear resinous layer 2 of a bluish-green color. The other side of the film basev was provided with a thin gelatin anchoring substratum 3. A gelatin silver chlorobromide emulsion was then coated onto the gelatin substratum and the resulting emulsion layer 4 was dried. The polyvinylpyridine acid dye salt layer had a density of 0.75 as determined by an ERPI densitoxneter. Its density was found to be suificient to permit the film to be used in a daylight loading camera spool.

A portion of the film was given a flash exposure and developed for 3 minutes in a developing solution made up by admixing the following components in the order named:

Water to make 1.0 liter Example If Another poly-2-vinylpyridine acid; dye ,salt was made: inna, manner similar to that describedin Example I. but substituting an e uivalent of Rontamine Green BX (Colour Index '593') for the dye-described in the precedingexampler A photog-raphic film element was prepared in a similar manner. and exposed, developed, and further treated as described in the example withgsimilar resu ts. Thep lyvinylpyridine acid dyesalt layer: had a. density o as determined bran li-PI- densitometer- Example 111 :Another poly-2-viny1pyridine-acid:dye saltwas prepared in thesame manner described in Ex:. ample I but substituting Pontamine. Green -S (Colour Index 583) for the dye of Example I. A photographic film element was prepared .from this die in a similar'manner and exposed, d6? veloped, and further treated after themanner describedin Example Iwith similar results. The polyvinylpyridine acid dye salt layer had adensity 01510.75: as, determined by an ERPI .densitometer.

Example IV A solution of 2.4 grams of the yellow dyestufi Tartrazine (Colour'Index 640), in 300 milliliters of water wasadded to 120 milliliters of a 10% 'solution of poly-2-vinylpyridine (which polymer was soluble in 1% aqueous acetic acid a'nd'iormed a clear, hard, resin-like film), in methanol containing 12 milliliters of glacial acetic acid. 150 milliliters of- 'a ,2% aqueous solution of ammonium hydroxide were added to the poly-2- vinylpyridine-dye solution, whereby a' salt of the acid dye with poly-2-vinylpyridine was precipitated fromsolutiomsaid salt being washed freely with cold water to remove excess dye. The salt was soluble in a 50/50 mixture of methanol and ethanol. When applied to a clear surface from such-a solution, a transparent, hard, resin-like yellow film was obtained. Seven grams of the above salt were dissolved with stirring in 365 milliliters of 95% ethyl alcohol and 255 milliliters of distilled water at 140- 150* F. To'this was added a solution composed oi 195 milliliters of distilled water, 28 milliliters of--95% ethyl alcohol and 24 grams of polyvinyl alcohol (completely hydrolyzed polyvinyl acetate, 4% aqueous'solution having a viscosity at-'C. of 25' centipoises). Eight milliliters of a 10% aqueous solution of n-cetyl betaine was then added and the total solution-stirred at 130 F. for 10 minutes. v I

A green sensitive cyan polymer emulsion, containing approximately 4% of a m-(3-methyl salicylamido) benzaldehyde polyvinyl acetal'of' the type described in Martin I]. S. application Ser. No. 29,921 filed May 28, 1948 now Patent No. 2,538,257, and 2.1% silver halide, was coated to form green-light-sensitive layer 5- on' cellulose nitrate film base 6 as shown in-Fig. 2 of'the-drawing which-ihadzpreviously' been treated. on: the reverse side with' a. solution of polyvinyl ialcohol (77%. hydrolyzedpolyvinyl acetate, 'having a yise cosity of 20i-30xcentipoises at; 20 .0.) containing dissolved thereinaquantity of the acid dye known as Ink Blue (Colour Index No. 706). l isintended to.v act as a non-halationlayer and is dischargeable during-processing. Oven-the cyan layer the dispersion of the polyvinylpyridine-Tartrazine salt described above was applied to form filter layer 8. Finally,.a.blue sensi.'-' tive magenta. polymer emulsionrcontaining approximately. 3% m [p 5(ethyl. carbonate 3, methyl 1' pyrazolyl)benzamidolbenzaldehyde polyvinyl acetal and 1.6% ofJ silver halide, was applied over the polyvinylpyridine-Tartrazine salt layer to form blue-light-sensitive layer 9.

In the film prepared in this manner, the polyvinylpyridine-Tartrazine salt layer acted as a filter layer to blue light, thus reducing print through" in the green sensitive cyan layer: The tendency of the Tartrazine dye molecules'to migrate: during coating wasalso greatly reduced.

Thecoated films after exposure were developed for 10 minutes in the following color developer-I:

p-Aminodiethylaniline .HCl grams,; j 2'15 Sodium sulfite (anhydrous) I- do 1.0.0 Sodium carbonate (monohydrate) .do. 2.9.25 Potassium bromide o- 2.0 Water to make 1.0 liter 1 The films were then washed forone minutesand fixed for fiveminutes in the following solution:

. 20.0 Water to make 1.0 liter (Dilute 1 part to 2 of water before using);

After. washing for 10 minutes, thefilmswere bleached in the following. solution for five min,- tes V Potassium ferricyanide grams s 100.0 Boric acid do' x 10.0 Borax do..

.50 Water to make 1.0 liter Films were, then washed two minutes and fixed again, for five minutes in the following solution:

Sodium thiosulfate crystalsgrams 200.0 Water to make 1.0 liter After washing for 10 minutes, the filmsrwere dried. v x i The yellow dye was removed-during processing.

A similar film elementjas; shown in Fig. 3 of the drawing containing-an additional colorforming layervcan be made by first'coating-onto the filmbase alayerl0 composed of one of'the yellow color-forming polyvinyl acetals of Mc- Queen U. S. application SenNo. 9',330-filed; :February 18, 1948, now Patent No. 2,513,190,, a layer ll of a. medium viscosity-polyvinyl alcohol from a 2% solution in 20 to 25%" aqueous ethanol is coated onto. the polyvinyl acetal layer. Upon the latter layer there are then'coated the layers described above. It is'processedin: like manner with similar results. i i

Example V This-layer 7 2,274,782 in 300 milliliters of water w'asia'dded to' 120 milliliters of a 10% solution of po1y-2-viny1- pyridine (which polymer was soluble in 1%. aqueous acetic acid and formed atclear, hard, resinlike. film), in methanol containing 12 milliliters of glacial acetic acid. 150 milliliters .of a 2% aqueous solution of ammonium hydroxide were added to the poly-2-vinylpyridine-dye solution, wherebya salt of the acid dye with poly-Z-vinylpyridine was precipitated from solution, said salt being washed freely with cold water to remove excess dye. The salt was soluble in a 50/50 mixture of methanol and ethanol. When applied to a clear surface from such a solution, a transparent, hard, resin-like film was obtained.

Seven grams of this polyvinylpyridine-dye salt were dissolved with stirring in 370 milliliters of 75% ethyl alcohol and 260 milliliters of distilled water at 140 to 150 F. To this was added a solution composed of 24 grams of polyvinyl alcohol (completely hydrolyzed polyvinylacetate, 4% aqueous solution havin a viscosity at 20 C. of 25 centipoises). Eight milliliters of a 10% aqueous solution of n-cetyl betaine were then added, and the total solution stirred at 130 F. for 10 minutes.

A multilayer film was then prepared substituting the above solution for that containing the polyvinylpyridine-dye salt of Example IV.

Processing was carried out as in Example IV with similar results.

In place of the particular dyes described in the foregoing examples, there may be used various other acid dyes which form salts with vinyl pyridine polymers. Among the other additional useful dyes are:

Colour Index No.

Pontachrome Black PV or Diamond Black PV 1'10 Pontacyl Light Green SF 670 Pontacyl Brilliant Blue A 714 Wool Violet S 50 Lithosol Red C 165 This invention has the advantage that it provides a new type of light-screening layer which may be readily prepared and is somewhat economical and effective. A further advantage is the fact that the dyes used and their light absorptive properties form an integral part of the layer and can be bodily removed with the layer. This is particularly advantageous in the case of the anti-halation layers.

The anti-halation layers of this invention are not dissolved by the alkaline developer or waterrinse baths used in the processing of a photographic element containing exposed silver halides. This means that the dyes do not contaminate the developer solutions or water-rinsebaths and, hence, the solutions have greater effective life. The layers, however, can be readily solubilized by the acid present in and at the concentration used in ordinary acid processing baths, e. g., acid-stop baths, acid fixing baths, acid hardening-fixing baths, acidbleachbaths, and reversal-bleach baths. The layers can be bodily removed during development if desired if an acid developing bath is used. The dye complexes have many advantages in the preparation of filter layers for multilayer film structures where their non-migratory nature prevents diffusion into and contamination of contiguous sensitized layers.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to'be limited ex ceptiasdefined by the claims.

What, is claimed is: g1 "1. 'A photographic element comprising a support, at least. one light-sensitive silver-halide emulsionlayer and a light-filtering; layer com,- prising a salt of a vinylpyridine polymer. which is insoluble in water but soluble in 1% aqueous acetic acid with an acid dye, said dye being 'absorbent of light. rays to which the emulsion layer is sensitive.

2. A photographic element comprising a lighttransmitting support bearing at least one lightsensitive silver halide emulsion layer on one surface of the support and on the other-surface of the support an anti-halation layer comprising a salt of a vinylpyridine polymer which is insoluble in water but-soluble in 1% aqueous acetic acid with an acid dye, said dye being absorbent of light rays to which the emulsion layer is sensitive. V 3. A photographic film element comprising a transparent film base bearing a gelatino silver halide panchromatic emulsion layer onone surface thereof and on the opposite surface an antihalation layer comprising a salt of a vinylpyridine polymer which is insoluble in water but soluble in 1% aqueous acetic acid with an acid dye, said dye being absorbent of light rays to which the emulsion layer is sensitive.

4. A photographic element comprising a sup-' port, at least one light-sensitive silver halide emulsion layer and a light-filtering layer comprising a salt of 'a"polyvinylpyridine. polymer which is insoluble in water but soluble in 1% aqueous acetic acid with an acid dye, said dye being absorbent of light rays to which the emulsion layer is sensitive.

5. A photographic element comprising a lighttransmitting support bearing at least one lightsensitive silver halide emulsion layer on one surface of the support and on the opposite surface of the support an anti-halation layer comprising a salt of a polyvinylpyridine polymer which is insoluble in water but soluble in 1% aqueous acetic acid with an acid dye, said dye being-absorbent of light rays to which the emulsion layer is sensitive. I W

6. A photographic film element comprising a transparent film base bearing a gelatino silver halide panchromatic emulsion layer on one surface thereof and on the opposite surface an antihalation layer comprising a salt of polyvinylpyridine'polymer which is insoluble in water but soluble in 1% aqueous acetic acid with an acid olye', sai d dye being absorbent of light raysto which'the emulsion layer is sensitive; ,7,- A photographic element comprising a sup: port, at least one light-sensitive silver halide emulsion layer and a light-filtering layer comprising a salt of a poly- 2 vinylpyridine polymer which is insoluble-in water but soluble in 1% aqueous acetic acid with an acid dye, said dye being absorbent of light rays to which the emulsion layer is sensitive.

8. A photographic element comprising a lighttransmitting support bearing at least one lightsensitive silver halide emulsion layer on one surface of the support and on the opposite surface of the support an anti-halation layer comprising-a salt ofa poly-Z-vinylpyridine polymer which is insoluble in water but soluble in 1% aqueous acetic acid with an acid dye, said dye beingabsorbent of light'rays to which the emulsion layer is sensitive.

9. A photographic film element comprising a REFERENCES CITED transparent film base bearing a gelatin) Silver The following references are of record in thehalidei1 panchromatic;5 emulsiontlayerf on onesiirfile of this paltntz face t ereof and on he opposi e sur ace an an ihalation layer comprising a salt of a, poly-2- 5 UNITED STATES PATENTS vinylpyridine polymer which is insoluble in water Number Name Date but soluble in 1% aqueous acetic acid with an 2,046,067 Gaspar June 30, 1936 acid dye, said dye being absorbent of light rays 2,099,341- Kenyon et a1. Nov. 16, 1937 to which the emulsion layer is sensitive. 2,448,507 Alles Sept. 7, 1948 WILLIAM RUSSELL SANER. 10 2,448,542 McQueen et a1 Sept. 7, 1948 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT AT LEAST ONE LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER AND A LIGHT-FILTERING LAYER COMPRISING A SALT OF A VINYLPYRIDINE POLYMER WHICH IS INSOLUBLE IN WATER BUT SOLUBLE IN 1% AQUEOUS ACETIC ACID WITH AN ACID DYE, SAID DYE BEING AB- 